jg williams's Comments

April 08, 2014

Why Falling Module Prices Lead to Lower-tilt Racking

Hi, more and more people will choose to use their energy on site rather than export it to the grid as this is generally worth more to the owner and gets round the increasing problem of lack of grid capacity in the local grid. A large turkey farmer in Germany with long thin sheds running north to south has deliberately chosen to put solar panels facing west and east as this gives him a steadier supply of solar generated electricity throughout daylight hours and in the summer benefits from up to 16 hours of daily daylight. The overall loss of solar output is about 10% but the midday surge of solar electricity, much of which would have been wasted (ie exported to the grid for a pittance), is avoided. As installation costs fall, this will become more common practice as SMEs seek to substitute the optimum amount of grid supplied electricity with 'home brewed' solar PV. Adding wind energy compliments solar energy well and reduces the amount of storage required for those SMEs choosing to go near 'off-grid' - the RMI's 'grid defectors'!

January 16, 2014

England's Clouds Part for Solar as Panels Carpet Fields

A good article. However, Cornwall in the SW of England is far from gloomy with an average of 1,706 hours of sunshine per year which is identical to Munich in the south of Germany. Unlike Munich, we have cool Atlantic summers, clearer skies and periodic gentle rain to wash our panels. Solar panels hate heat and dust. Hence, solar PV output is higher than in southern Germany. Gloomy, indeed!

December 25, 2013

The Big Question: What Is the Future Utility Business Model?

This article misses the point as it looks at RE as being an alternative to centralised power generation. Instead, consumers at residential, farm and commercial level are adopting RE as a 'Home Brew' or 'Moon Shine' alternative to grid supplied electricity as brewed locally solar PV or sub 500kW wind generated electricity is already less than $0.09/kWh, about half the price of the grid supplied alternative that has to be paid for from taxed income. Storage technologies at this scale are now becoming affordable and will be augmented by EV batteries and automatic diversion of surplus home brewed electricity to heat water or top up an ice store.

The grid will be used 'in extremis'. In many cases, the home brewed electricity will be DC as with the advent of LED lighting there are few domestic appliances that will require AC. This will remove the cost of inverters while bestowing near autonomy of power supply at the residential and commercial levels.

This is a severe threat to the 120 year old grid supply system that may have had its day - and a long run at that. As more and more consumers switch to home brew, there will be less and less customers to pay for the cost of the grid system hastening its demise as its survival will depend on raising the cost of electricity that in turn will accelerate the switch to home brew. Raising finance for replacement centralised power stations will become harder and more expensive - atrophy of the grid looms.

The 83,000 Indian villages that are waiting for a grid connection - tantamount to waiting for Godot - will be the first to embrace home brewed electricity now that prices have tumbled for solar PV. Companies such as Spinetic Energy Ltd will offer affordable wind-panels (an American football goal post with 2m tall vertical axis turbines in a fram above the cross bar) that can be turned into wind-fences to supplement solar PV electricity, especially during the monsoon season. They will certainly spurn inverters and use DC. The range of DC powered applications found in the catalogue at www.atlants.net is awesome and growing. There are analogies here to the way that Kenyans have a 74% smart phone penetration and have leapfrogged PCs and laptops; or the East Germans, when the wall came down, were nonplussed by Deutsche Telekom's vast investment in fixed line telephones - they all bought mobile phones instead. The 1.6 billion people without electricity will at last have their own electricity - why would they want to be connected to a utility company?

December 28, 2013

The Big Question: What Is the Future Utility Business Model?


Making those who generate their own electricity pay cripplingly high charges for their occasional use of the grid when they have run out of renewable energy (solar, wind, hydro, and stored) will result in businesses, farms or householders buying small diesel gensets for their back-up. Your proposal is similar to insisting that people continue to for pay horse-drawn stagecoaches long after the advent of the train, automobile and aeroplanes, or insisting that Kenyans have to pay for a fixed line telephone system when they are all using mobile/smart phones. The market gives people the choice.

I generate 4,000 kWh/yr of solar electricity from a ground-mounted array in my garden that cost £6,000 and should last for 30 years and my heating and hotwater is provided by an Austrian wood-pellet boiler. Both provide me with what I need at less than 5p/kWh ($0.08). Buying electricity from the grid would cost me 20p/kWh ($0.36) from taxed income. As a 20% taxpayer, the grossed up cost is 25p/kWh - why would I do that? This is what utility scale centralised power generation is up against. Regulation to ensure it remains profitable will only make the retail cost of grid supplied electricity yet more costly. It's cost at point of use that matters; not cost at point of centralised generation.

To illustrate this, one needs to look at why I am charged 25p/kWh for electricity generated by a coal power-station 200 miles away (the UK is meant to be a small country!). The cost is 4p/kWh at point of generation. Incidentally, the coal power station is 35% efficient and its cooling towers dominate the landscape as there is no industry or town that can take the wasted heat. There are transmission losses over the 200 mile journey to my house. The electricity is sold to the National Grid at 400kV who in turn sell it on to a Distributed Network Opertator who passes it on at 132kV, 11kV and finally it is bought by one of six supply companies (one of whom probably owns the power-station) who sells it on to the consumer. Each makes a turn (oddly called 'value added') and I finish up paying five times more than it cost to generate as the daytime tariff is higher than the night-time tariff.

December 18, 2013

Are Electric Vehicles Already Halfway to Market Dominance?

Why aren't we developing EV farm tractors? Range, space and weight of batteries are not issues. Farms have lifting equipment that can change heavy rechargeable battery packs. Farms have plenty of space to recharge battery packs with solar and wind generated electricity. Remove the heavy diesel engine and replace it with a heavy battery pack and lightweight electric motors. Farm brewed electricity is already far cheaper than diesel fuel that will have been extracted, refined and transported from thousands of miles away. No emissions, too.

November 28, 2013

Should Solar Face West not South?

Hi Chris,

There is a German turkey farm with long sheds with the roof-line running north to south where they have put panels on the east and west facing roofs as this gives the smoothest match to actual demand, avoids a wasted peak at midday and in the summer months when the sun moves through 270 degrees, they generate solar electricity for up to 17 hours of daylight. The overall loss in generation is about 10%, but far less than 10% is wasted and either dumped or exported to the grid at a very low price. This method also reduces the cost of the hook-up to the grid because the midday peak output is considerably less.

August 27, 2013

Solar Energy Powers Rural Texas Ranches

Home Brewed Electricity: It’s interesting to calculate Dr Bard’s cost of his home brewed electricity. After his tax refund, the 10kW system cost him $25,200. In the UK or Germany, a 10kW system would have cost less than $15,000 if installed today.

I have seen solar PV panels in the UK that are over 30 years old and generating 90% of the electricity generated in their first year. Dr Bard is generating slightly over 16,000 kWh per year. Over 30 years he should generate about 480,000 kWh. Assuming that inverters have to be replaced during the 30 years costing, say, $6,800, the lifetime cost of the system is $25,200 + $6,800 = $32,000.

The cost of each home brewed kWh is therefore $32,000 divided by 480,000 = 6.7 cents/kWh. According to Wiki, the retail cost of US electricity is 8 to 17 cents. Taking a middle price of 12.7cents, over 30 years, Dr Bard will save $28,800.

However, he would have paid for grid electricity out of taxed income. Assuming a marginal income tax rate of 25%, the real benefit when grossed up is $28,800 divided by 0.75 = $38,400 at today’s prices. His Year 1 benefit is (16,000 x 0.06) divided by 0.75 = $1,280.
Assuming inflation runs at 2.5% per year, over 30 years, the total gain is £56,195 and the $32,000 investment is paid back after 11 years or in 9 years’ time when Dr Bard will be 78, I would hope well within his lifetime!

He might also look into using any surplus solar electricity for pumping water from his two wells to an elevated storage tank and then running it back down to the wells to generate hydro-electricity when farm electricity demand exceeds supply (at night-time etc). Electric pumps these days can be reversible and have efficiencies in excess of 80%. In my view, water pumped storage is the simplest of available batteries and is much neglected. Most farms could become electricity self-sufficient by using wind, solar and pumped-storage. Chemical batteries are all expensive and have limited lives.

August 09, 2013

Energy Storage: Rural Electrification’s Backup

Why make storage so complex? The easiest form of storage is to use surplus solar or wind generated electricity to pump water from a lower reservoir/storage tank/stream to a higher storage tank (preferabley one that is also spring fed. When demand exceeds the renewable electricity supply, the water is run back down hill to the lower tank through a reversed turbine to generate hydro-electricity. We appear to be in the thrall of the battery and inverter industry. Most electrical appliances nowadays prefer to run on DC (LED lighting etc). Keep it simple....

July 20, 2013

How Do Storage Systems in Photovoltaic Installations Work?

Best means of electricity storage for a farm in hilly country is to pump water between a lower tank to a higher tank and then reverse the pump to generate hydro-electricity when you need the electricity. In the UK we receive feed-in-tariffs for pumping the water uphill using either wind or solar PV and then further FITs when we generate the hydro-electricity. The Grand Old Duke of York would have been delighted. If scaled properly, there should be no need to draw on the grid and this would just be used 'in extremis' when there has been a prolonged windless and cloudy period. This would save on the exorbitant hook-up charges levied by the local grid operator as the farmer would no longer have surplus renewable electricity to export to the grid. Farms have a wide range of relatively cheap slurry tanks that can be used for pumped storage. If the upper storage tank can be sited below a spring, there would be natural filling of the tank to supplement the pumped storage. This is little different from the Victorians who stored spring water in reservoirs for use when milling. Not everything needs a technical solution!

Gage Williams, Cornwall, UK

July 19, 2013

Could Renewable Energy Stop UK Lights from Going Out?

As the article portrays, time is running out with the threat of brown or black outs by the winter of 2015. However, one major advantage of switching to renewables is the speed with which they can be installed. The UK's largest solar PV array, 34MW comprising 130,000 solar PV panels at Wymeswold Airfield, was installed in under eight weeks during January and February 2013, a period of dreadful weather. The earliest that the next planned gas fired power station will come on line is 2016; Hinkley C by 2022 if all goes well.

May 14, 2013

Energy Expert Predicts Solar Could Upend Major Utility in California on Price

I would be interested to know whether the study has included income and sales tax when assessing the 'point of sale' costs. Home brewed electricty is tax free; the electricity bought from PG&E that it replaces would have had to have been paid from taxed income. While I do not know Californian income tax + sales tax, in the UK the basic rate of tax is 20% plus a sales tax of 5%. In which case, to pay for a kWh of PG&E electricity costing 31 to 35 cents, the consumer would have to have earned a grossed up 41.3 to 46.6 cents. At the projected 54 cents in the article, this would rise to a grossed up cost of 72 cents/kWh. No wonder the utility companies are so fearful of 'home brewed' electricity - 'socket parity' was achieved long ago.

In the UK and Germany, we have nearly reached the goal of $1.50/Wp and passed the $2.00/Wp target about six months ago. My 4kWp ground-mounted array in March 2012 in the UK cost $9,300. It will generate 4,000 kWh per year for 30 years = 120,000 kWh. Adding two new inverters during those 30 years brings the capex up to $12,000 giving a cost in cloudy southern UK of 10 cents/kWh. California has better insolation than Cornwall (we have about 1,000 kWh/kWp/yr) and it should be possible to drive the tax free 'home brew' cost below 7 cents/kWh.

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