Solar Case Study

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4.7.51. Solar Case Study:

1. In compliance with ISO 14001 Environmental Management Standard, a mission has been agreed to evolve towards 100% energy self-sufficiency within the next five years.

2. A typical domestic installation of 16 solar panels rated at 250 watts provides a 4KW solar roof that is connected to the normal domestic electric supply with an inverter to balance voltages.

3. No moving parts and no maintenance, other than the occasional washing down of the solar panels.

4. A solar power meter is installed to measure what units of electricity are generated.

5. Readings are taken quarterly and sent on-line to Scottish Power who administers the feed-in-tariff payment on behalf of the Government.

Foxleys Case Study:

1. Investments of about 6000 pounds were secured in 2013 to fund a very typical domestic 4KW solar generation site. The mission was to create documented evidence on a year by year basis that the net cost of domestic electric energy can be reduced towards zero.

2. The government guaranteed twenty-year feed-in-tariff revenue is tax free and index linked. Based on 2014 prices, revenue over twenty years will be at least 14,000 pounds, however that excludes the value of "free" electricity that will be used to a value of 9,000 pounds. An investment of 6000 pound to pay an indexed-linked tax-free guaranteed quarterly income worth 23,000 pounds over twenty years is commended.

3. Maintenance is reduced to annual washing the solar panels and a new inverter (costing 500 pounds) may be needed every ten years. No moving parts are involved and expectations are that 3800 units of electricity will be generated in a typical year.

4. It is worth noting that solar panels like many electric components work best at low temperatures. A cold January sunny clear day may generate more than a hot hazie July day.

Benefits:

1. The simple economic benefits of the investment versus the feed-in-tariff index-linked payments is self-evident. The initial payment rate was just over 15 pence per unit and that has increased to 17 pence per unit at a time when metered electricity costs about 12 pence per unit. This is index-linked and tax-free income - very few investments carry such benefits.

2. The hidden benefit is that all electricity generated may be used free-of-charge and free of VAT. With a typical estimate of 3800 units being generated in a year, that free electricity could be worth 450 pounds. Electricity generated and not used is a benefit to the local electric distributor who will sell it to other people. Free electricity not only has a benefit of 12 pence per unit, but is also free of the five-percent VAT paid on metered supplies.

Results:

1. In Oct 2013 and Energy Performance assessment was undertaken with a rating of B85. A plan to increase this towards A98 included LED low-voltage lighting and battery power storage. Energy assessment was that electric energy had an annual cost in the order of 1200 pounds.

2. 1 May 2014 to 30 Apr 2015 saw metered electric usage drop to 9000 units and 3800 units generated. In cash terms, metered payments were 1080 pounds and feed-in-tariff revenue was 576 pounds.

2. 1 May 2015 to 30 Apr 2016 saw metered electric usage drop to 6200 units and 3782 units generated. In cash terms, metered payments were 744 pounds and feed-in-tariff revenue was 643 pounds.

3. 1 May 2016 to 30 Apr 2017 saw metered electric usage drop to 5300 units and 3284 units generated. In cash terms, metered payments were 585 pounds and feed-in-tariff revenue was 568 pounds. For five months of the year, monthly costs were negative and for seven months, metered electricity had to be paid for. An extra battery will enable the property to be self-sufficient for seven months and pay for top-up electricity for five months of the year.

Facilities Management:

1. Foxleys may not be as typical as it was planned because a large number of computers run 24*7 and air conditioning is used when needed. The property is manned 24*7, large monitors are used in a real-time monitoring environment and many lights are used 24*7.

2. The initial mission to have the electric energy cost matched by feed-in-tariff income will be achieved in five years. More solar panels are needed to capture energy earlier in the morning and trees at the bottom of the garden cast a shadow so evening solar power is reduced. Solar panel cost has reduced and a lot more solar panels could have been deployed and will be deployed in the future.

3. Batteries to hold electricity captured during the day to be used in the evening is mandated - an electric car driven by "free" electricity will be very cost effective. LED lights and LED screens have been a major part of electricity cost management. Excessive levels of insulation has considerable benefits, not only in the winter, but also in the summer.

4. Solar air pumps may be able to reduce the cost of air conditioning and provide clean filtered air to all inhabitants.

How does it work:

1. As an Environmental Management policy, meter readings are captured on the first day of every calendar month. Electric meter readings are shared with the energy provider using an online web form - it takes a few moments to enter the reading.

2. Once every three months, the solar meter reading is shared with Scottish Power using the "feed-in-tariff" link from the home page. The feed-in-tariff number is entered together with the reading and date - less than 4 minutes per year. Within 30 days, Scottish Power on behalf of the Government pay the applicable amount into the registered bank account.