Chapter 2: Install farm green energy harnessing system

Farm green energy systems have become essential in modern agricultural engineering, offering sustainable power solutions that reduce reliance on fossil fuels and lower operational costs. Installing these systems requires a comprehensive understanding of the tools and equipment specific to the agricultural environment in Kenya, where diverse farm sizes and terrains influence the choice and use of machinery. This chapter focuses on the critical tools and equipment necessary for effective installation, ensuring that agricultural engineers can design, implement, and maintain green energy systems efficiently on Kenyan farms.

2.1 Relevant tools and equipment required to install a farm green energy system

Installing a farm green energy system is done in stages: clearing and setting out the site, digging and building the bases, mounting and assembling the equipment, joining the cables or pipes, and testing the finished work. Each stage needs its own tools, and the installer lists them from the system design and the site survey before going to the farm. A mixed farm that adds a biogas digester for cooking fuel and a solar array for a grain dryer, for example, needs clearing tools, an excavator, bricklaying and concreting tools, a pipe-jointing set, electrical hand tools and test instruments, all on site at the right time.

The seven sections below take the tools in turn. Hand tools come first because they are used at every stage. Machinery for clearing the site follows, then the installation kit, the building tools, the instruments for checking the work, and the pipes and fittings that carry gas and water. Excavators come last, but on a real job they work early, as soon as the site is cleared and set out.

2.1.1 Hand tools

Hand tools are the tools an installer holds and powers by hand or with a small battery or mains drill. On a flower farm fitting a solar pumping system beside a greenhouse, one installer may use a tape measure, a spade, a spanner, a screwdriver and a crimping tool within a single morning. Good hand tools make connections tight and accurate, and poor or damaged ones loosen bolts, strip screw heads and cause electric shocks.

Care and safe handling of hand tools

Hand tools last longer and cause fewer injuries when they are kept in good condition and used for the job they were made for.

• Clean and dry after use: Wipe off soil, cement and moisture and put a light film of oil on bare steel, so that spanners, saws and spades do not rust.
• Keep insulation sound: Replace any screwdriver, plier or cutter whose insulation is cracked or worn through, because exposed metal under it can carry current to the user's hand.
• Use the right tool: A spanner of the correct size grips the whole nut, while a plier used on a nut rounds its corners, and a screwdriver used as a chisel breaks.
• Wear protective equipment: Gloves protect the hands from sharp edges and hot metal, safety boots protect the feet from dropped tools, and safety glasses protect the eyes when cutting or chiselling.
• Carry and pass tools safely: Use a tool belt or bag when working on a roof or frame so that nothing drops on someone below, and hand tools over handle first.
• Store in a lockable box: Keep tools together in a box or on a rack at the end of each day, so that none is lost and the work area is free of trip hazards.

Checking a hand tool before use

1. Look at the handle for cracks, splits or a loose head, and replace any tool with a damaged handle.
2. Check the working end: a spanner jaw that has spread, a screwdriver tip that is rounded, or a saw blade with missing teeth will not do the job properly.
3. For insulated tools, run a finger along the insulation and look for cuts, bubbles or bare metal.
4. Check that crimping tools close fully and release freely, and that wire strippers cut only the insulation.
5. Check the markings on a torque wrench and set it to the value required before each use.
6. Remove any tool that fails these checks from the toolbox and report it, so that it is repaired or replaced before the next job.

2.1.2 Land clearing machinery

Land clearing machinery removes bush, trees, stumps and rubbish so that an installation has a firm, open and unshaded site. A solar array needs ground free of tall plants and trees that cast shade, a biogas digester needs a clear area with room for a pit and a feed point, and a wind turbine needs a clear approach for its tower. On an overgrown, gently sloping plot at the edge of a tea estate, a team may start with brush cutters around the rocks and stumps and then bring in a tractor with a slasher to cut the open grass.

An excavator can also pull out stumps and roots, but because it is used for digging as well, it is described under Excavators.

Choosing machinery for the site

The machine is chosen from the site conditions, so that clearing is done quickly without removing more cover than the system needs.

• Area to be cleared: A small plot for a farm pump may need only brush cutters, while a large ground-mounted array can justify a tractor or bulldozer, because hand clearing would take too long.
• Type of vegetation: Grass and light bush are cut by slashers and brush cutters, whereas large trees and stumps need chainsaws, bulldozers or excavators.
• Slope and ground condition: Steep or stony ground may be unsafe for wheeled tractors, and soft wet ground can bog down heavy machines, so tracked machines or hand clearing are used instead.
• Soil protection: Clearing in dry weather avoids deep ruts and compaction, and leaving a grass cover on the ground around the cleared area reduces soil erosion.
• Access to the site: Large machines need a track wide enough to reach the site and, if they arrive on a low-loader, a place to unload.

Safe operation

• Walk the site first: Look for rocks, holes, termite mounds, beehives, snakes, boundary markers and buried or overhead lines before any machine starts.
• Keep people away: Other workers stay well outside the working area of a machine and a chainsaw, and the operator must be able to see them.
• Wear the right equipment: Chainsaw operators wear a helmet with visor, ear protection, cut-resistant trousers, gloves and safety boots, and brush cutter operators wear eye and ear protection as well.
• Check permits and the owner's wishes: Cutting large or protected trees, or clearing a large area, may need approval from the authority concerned, and the farm owner should agree in advance which trees stay.
• Service machines: Check fuel, oil, blades and guards before work, because a loose blade or a broken guard on a rotating cutter can throw parts at high speed.
• Dispose of cleared material properly: Stack branches and roots away from the installation, and do not burn them close to dry grass, fuel stores or wiring.

2.1.3 Green energy installation kit

A green energy installation kit is the set of mounting, joining, protecting and earthing items supplied with, or chosen for, one system so that it can be assembled correctly. The main electrical components of a solar system, such as the array, charge controller, battery bank and inverter, are selected in design. The kit covers the parts that hold them in place and connect them. On a poultry farm putting solar panels on a house roof, the kit might contain rails, roof hooks, clamps, cable, connectors, a fuse box and an earth rod.

The contents depend on the energy source:

Unpacking and checking the kit

1. Compare each item with the packing list supplied by the seller, and note anything missing or wrongly supplied.
2. Look for damage from transport, such as bent rails, cracked connectors, scratched cable insulation and broken seals.
3. Read the ratings on the labels of fuses, cables, isolators and connectors, and confirm that they match the design.
4. Keep the maker's installation manual and the drawings with the kit, and follow the order of assembly they give.
5. Sort the parts by stage of work, for example foundation, mounting, wiring and testing, and keep small items such as bolts and washers in labelled containers.
6. Store the kit in a dry covered place on site, off the ground, with cables coiled loosely and connectors capped so that they stay clean.

Care of the kit on site

• Protect from the weather: Cable and plastic fittings left in the sun become brittle, so keep them covered until they are installed.
• Do not mix connectors: Plug-in connectors from different makers may fit loosely and overheat, so use matched pairs unless the maker states that they are compatible.
• Handle panels carefully: Carry panels upright by the frame, with two people for large panels, lay them down gently, and never stand on them or lean them against a wall where they can fall.
• Keep records: Note the serial numbers and ratings of installed items, because this information is needed later for inspection and repair.

2.1.4 Construction tools and materials

Construction tools and materials are used to build the bases, frames, walls and enclosures that support the energy equipment. A maize store with a solar-powered drying fan needs concrete footings for the frame, a plinth for the inverter cabinet and a sealed channel for the cables. A biogas digester needs a lined pit and walls that do not leak. A wind turbine tower needs a deep concrete base that resists overturning in wind.

Construction materials

• Cement, sand and ballast: These make concrete for footings, plinths and tower bases, and the mix proportions follow the design rather than a guess on site.
• Reinforcement bars and binding wire: Steel bars carry tension in concrete, and they must be clean, correctly spaced and covered by concrete.
• Bricks or blocks, mortar and waterproof plaster: These form digester walls, pump houses and equipment enclosures, and the plaster seals a digester so that gas and slurry do not leak.
• Steel and aluminium sections: Angle, channel and tube are cut and joined to make frames, and they need protection against corrosion.
• Anchor bolts and chemical anchors: These fix rails, frames and tower bases to the concrete, and they must be set to the depth and spacing given by the maker.
• Paint, primer and sealant: Cut and welded steel is cleaned and painted, and joints and cable entries are sealed to keep out water.
• Timber for shuttering and props: This holds fresh concrete in shape and is removed after the concrete has hardened.

Placing and curing concrete

Fresh concrete is placed in the shuttering in layers, compacted so that no air pockets remain, and levelled with a straight edge. It is then covered and kept damp for several days, as the design specifies, so that it gains full strength. Loads such as panel frames or tower sections are fixed only after this time.

2.1.5 Testing tools and accessories

Testing tools are instruments that measure the quantities in a system and show whether it has been installed correctly and safely. A technician who has connected a row of solar panels on a fish farm uses a multimeter to read the voltage before connecting the controller, and a clamp meter later to read the current. The way each result is judged and the order of the tests are covered in Methods of testing installed farm green energy technologies. This section covers the instruments and accessories.

Accessories

• Test leads and probes: Leads with good insulation and shrouded plugs are needed for safe contact with terminals, and damaged leads give false readings and risk shock.
• Crocodile clips and adapters: These hold the test lead on a terminal so that both hands are free, and they must be fully insulated except at the tips.
• Non-contact voltage detector: This pen-type tester signals the presence of alternating voltage on a conductor and is used as a first check before touching mains wiring. It does not detect direct current, so it gives no warning on panel, battery or controller cables, which are checked with a multimeter.
• Soapy water in a spray bottle: A soap and water mixture brushed on gas pipe joints shows bubbles where gas leaks.
• Labels, marker and notebook: These identify tested circuits and record readings, dates and the instrument used.
• Spare batteries and fuses: These keep instruments working, and meter fuses must be of the type the maker specifies.

Care and safe use of testing tools

• Select the correct range and function: Using a current setting across a voltage source can blow the meter's fuse and cause a flash, so check the dial and lead sockets before every measurement.
• Respect the rating: Use instruments only on circuits within their stated voltage and safety category, because a meter used above its rating can fail dangerously.
• Treat solar circuits as live in daylight: Panels produce voltage whenever light falls on them, and direct-current circuits can form arcs when broken under load, so isolate and cover panels before working on them.
• Keep instruments dry and clean: Store them in their cases, away from rain and dust, and handle them gently because they are precision instruments.
• Check instruments regularly: Compare a meter with a known source or have it calibrated when the maker advises, so that readings can be trusted.

2.1.6 Pipes and fittings

Pipes and fittings carry gas, slurry and water in biogas, pumping and small hydropower systems. On a pig unit with a biogas digester, a gas pipe runs from the digester to the kitchen stove, and a slurry pipe carries digested slurry to a storage pit. On a farm with a solar pump, a suction pipe, a delivery pipe and valves carry water from a borehole or river to a tank. If the wrong pipe or a poor joint is used, gas escapes, water is lost and the system loses pressure.

Selecting pipes and fittings

• Fluid carried: Water, biogas and slurry behave differently, and biogas contains moisture and hydrogen sulphide, which corrodes some metals, so plastic pipe or protected metal is used on gas lines.
• Pressure rating: The pressure class marked on a pipe must be higher than the highest pressure the system will meet, including pressure surges when a valve closes quickly.
• Size: Pipe diameter follows the design flow, because a pipe that is too narrow slows the flow and makes a pump or a burner work badly.
• Exposure to sunlight: Pipe that runs above ground must be UV-resistant or covered, because sunlight makes some plastics brittle.
• Compatibility: Fittings and valves must be of the same size and thread type as the pipe, and mixing materials at a joint requires proper adaptors.

Cutting and joining a uPVC pipe with solvent cement

1. Measure the pipe length and mark it, allowing for the depth of the socket on each fitting.
2. Cut the pipe square with a fine-tooth saw or pipe cutter, then remove burrs from inside and outside the cut end.
3. Dry fit the pipe into the fitting and mark the depth of insertion, then separate them.
4. Clean the pipe end and the socket with a clean cloth, and wipe with the cleaner the cement maker recommends.
5. Brush solvent cement evenly onto the pipe end and the socket, working quickly because it dries fast. Work in open air or good ventilation, keep the cement away from flames and wear gloves, because it gives off flammable fumes.
6. Push the pipe into the socket with a quarter turn, hold it for the time stated by the cement maker, and wipe off surplus cement.
7. Leave the joint undisturbed for the curing time stated on the cement tin before the pipe is put under pressure.

Laying pipes

Pipes laid underground go on a bed of sand or fine soil free from sharp stones, and gas pipes slope gently towards a water trap so that condensed water drains out and does not block the line. Valves are fitted where sections may need to be shut off for repairs, and exposed pipes are supported at regular intervals, so that they do not sag.

2.1.7 Excavators

An excavator is a machine with a hydraulic arm and bucket that digs, loads and moves large volumes of soil much faster than hand digging. It is used to dig trenches for underground cables and pipes, pits for biogas digesters, footings for solar frames, and holes for wind turbine towers. On a farm that clears land for a large ground-mounted array, an excavator can dig a long cable trench in far less time than a gang of labourers with hand tools.

Working out the volume to be dug

The volume to be dug decides the size of machine and the time needed, and gives the amount of soil to be carried or stored.

Example 1: A cable trench for a solar pumping system on a horticulture farm is 120 m long, 0.4 m wide and 0.6 m deep.

Volume = length × width × depth

Volume = 120 m × 0.4 m × 0.6 m

Volume = 48 m² × 0.6 m = 28.8 m³

The trench has 28.8 m³ of soil to be dug.

Example 2: A circular pit for a small biogas digester has a diameter of 3 m and a depth of 2.5 m.

Radius = diameter ÷ 2 = 3 m ÷ 2 = 1.5 m

Area of the circle = π × radius² = 3.1416 × (1.5 m)²

Area = 3.1416 × 2.25 m² = 7.0686 m²

Volume = area × depth = 7.0686 m² × 2.5 m = 17.67 m³

The pit has 17.67 m³ of soil to be dug. Dug soil takes up more space than it did in the ground, so the spoil heap is larger than these figures suggest.

Planning and carrying out the excavation

1. Set out the trench or pit with pegs and string line, using the dimensions on the drawings.
2. Find out where buried cables and pipes run, ask the farm owner and the service providers for their routes, and mark them on the ground before the machine arrives.
3. Mark a safe exclusion zone round the working area and keep people, animals and vehicles outside it.
4. Place the spoil heap on one side of the trench, well back from the edge, so that its weight does not cause the sides to collapse and the other side is free for laying cable or pipe.
5. Dig in layers, checking depth and width often with a tape and a levelling staff, and keep the bottom of the trench to the required fall or level.
6. Trim the bottom of the trench by hand, remove sharp stones, and place a bed of sand where the cable or pipe requires it.
7. Keep people out of deep trenches unless the sides are sloped or supported, and fill the trench in layers after the cable or pipe has been laid and inspected.

Safe operation and daily checks

• Qualified operator: Only a trained and authorised operator works the machine, and a second person guides the operator when the view is blocked.
• Keep clear of the swing radius: The body and arm swing round, and no one should stand within the area the machine can reach.
• Stay away from overhead lines: Keep the arm and bucket well clear of power lines, and treat any buried cable found as live until it is proved otherwise.
• Work on stable ground: Park on level firm ground, never dig at the base of a slope the machine stands on, and lower the bucket to the ground when leaving the machine.
• Check before starting: Look at fuel, engine oil, hydraulic oil level, hoses for leaks, track or tyre condition, and bucket pins and teeth.
• Grease and clean: Grease the points the maker marks and clean the machine at the end of the day so that damage is easy to see.
• Protect farm operations: Plan digging so that it does not cut farm tracks, water lines or crop areas that are still in use.

Chapter Summary

This chapter explored the various tools and equipment necessary for installing a farm green energy system, including hand tools, land clearing machinery, specialized green energy installation kits, construction tools, testing accessories, pipes and fittings, as well as excavators. It then examined different types of green energy systems suitable for farms, highlighting their distinct features and applications. The discussion proceeded to cover the materials used in these installations, emphasizing their availability and suitability for sustainable energy projects. Detailed installation procedures were presented to guide effective and safe deployment of green energy technologies on farms. Finally, the chapter addressed methods for testing the installed systems to ensure functionality, efficiency, and reliability, thereby supporting sustainable agricultural practices.