Our Energy Group meeting on Thursday 12 May included an informative talk by Peter Leith-Wybrow of Applied Solar Wind Solutions in response to the question “What strategies can we develop to reduce the carbon footprint of The Grove?”
The need for sustainable sources of energy, coupled with rising energy costs and government incentives, is stimulating a wave of innovation. Emerging technologies provide opportunities for entrepreneurs to combine them into new energy solutions, a process known as technological convergence.
Peter's talk described a renewable energy solution based on the convergence of three essential elements, generation, storage and finance.
While rooftop photovoltaic panels have become the conventional approach for domestic renewable energy, they are far from the end of the story. Innovation continues to increase the benefits, and reduce the costs, including the cost of energy required to manufacture the silicon cells. The solution Peter outlined inevitably starts with an acronym STSC or Sun Tracking Solar Concentrator. Sun tracking means that the panels automatically align them selves to face directly towards the sun, all day, and in all seasons.
This overcomes a major inefficiency with conventional solutions with fixed orientation usually determined more by the slope of the roof than the sun. It also a requirement for solar concentration.
The Solar Concentrator part of the solution uses an array of moulded lenses, each concentrating the sun onto a solar cell the size of a postage stamp. An innovative cooling system enables these cells to run cooler than conventional PV panels.
This technology was developed by UK based Whitfield Solar and has now been acquired by an Italian/Portuguese consortium.
One of the most common misconceptions about using solar energy is that it is unsuitable for base-load power because the sun doesn't shine at night. This objection is overcome by storing energy while the sun is shining, so that it is available when needed, day or night.
Battery technology has advanced dramatically in recent years driven largely by demands of mobile phones and electric cars. Both of these require small size and light weight. On the other hand storing solar generated electricity demands the ability to store large amounts of energy and deliver it over an extended period of time.
One innovative solution to this requirement is the 'Flowing Electrolyte' battery. In conventional batteries, energy is stored by changing the chemical composition of the plates as the battery charges. More capacity required more and bigger plates. In the flowing electrolyte battery energy is stored by changing the chemical composition of the liquid electrolyte. Large quantities of the 'energised' electrolyte can be stored in tanks, allowing for very large capacities.
This principle has been applied in the zinc-bromine battery module (ZBM) developed and manufactured by Brisbane based company RedFlow and comes in a range of sizes.
Most electricity consumers are unaware of the mechanisms of the Australian National Energy Market (NEM) which mediates the problem of using coal fired power stations that deliver a steady output to satisfying a highly variable energy demand. Because of this discrepancy between supply and demand the price of electricity in the spot market is highly volatile. When the demand exceeds the available supply the spot price can spike to several hundred times the average price for short periods.
Exchange between electricity producers and electricity consumers is facilitated by the Australian Energy Market Operator (AEMO). Scheduled generators submit offers every five minutes of every day. From all offers submitted, AEMO’s systems determine the generators required to produce electricity based on the principle of meeting prevailing demand in the most cost-efficient way. AEMO then dispatches these generators into production.
A dispatch price is determined every five minutes, and six dispatch prices are averaged every half-hour to determine the spot price for each trading interval for each of the regions of the NEM. AEMO uses the spot price as the basis for the settlement of financial transactions for all energy traded in the NEM.
Anyone who has the capacity to generate significant volumes of renewable energy, and to store it to meet peak demand, has a valuable resource to offer in the National Energy Market.
While it is possible for any household to purchase a domestic ZBM energy storage facility, the financial benefit would be limited to the standard feed-in tariffs, and the ability to use storage to mediate between times of peak supply and times of peak demand.
An alternative approach is for a group of investors to initiate a large scale project to deliver renewable electricity to the grid on the same terms as a conventional power station. The facility would be a 'registered generator', participating in the Australian National Energy Market.
The facility would not need to be located close to the investors/consumers. It could be established in a location with ideal conditions for solar energy (say west of the great dividing range) and feed its renewable energy into the grid at times of peak demand.
A larger facility would be more efficient due to economies of scale.
The benefit to the environment, and the reduction of greenhouse emissions, would be enhanced by the optimised location.
The financial benefit to investors would be increased, but would be derived from energy market trading, rather than the feed-in tariff at the domestic electricity meter.
For more information contact: Peter Leith-Wybrow