A sustainable property in Flowerdale

Last weekend we visited the sustainable property of Trent and Vikki who live in Flowerdale, roughly 60km north of Melbourne.  

Our visit was prompted by buying several hundred tree guards and stakes that Vikki and Trent had listed on ebay. When chatting to them on the phone beforehand to arrange pickup we discovered Trent and Vikki are committed environmentalists who live off-grid on a 70 acre property with solar-powered electricity, solar hot water and a composting toilet.  Needless to say we were looking forward to meeting them and seeing their property.

Trent is a full time environmental campaigner and Vikki is a nurse who strongly believes that one can't be a humanitarian without also being an environmentalist. Both are actively involved in campaigning to save the endangered Leadbeater's possum in the Central Highlands.

In 2009 the Black Saturday bushfires tore through Flowerdale. Fortunately, Trent and Vikki managed to save their home. A few months after the fires, they were married on the property.  On the wedding day, rather than bringing gifts, the wedding guests helped the bride and groom plant 2000 trees. Today those trees cover the hillside behind the house.

After a cup of tea and a nice chat by the fire, Trent and Vikki were kind enough to give us a tour of their property.  Trent built both the house and the barn himself, living in the barn loft while he built the house. Both buildings are clad with waste wood from a sawmill on the Murray River. But he didn't stop there - Trent even made the dining table and seating from sustainably sourced Ironbark. 
 

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The barn hosts a PV installation

 And a building adjacent to the barn holds the battery bank that stores the captured energy.

Here's Trent and Vikki's son Jarrah showing us how it all works:

The family grows their own food, having a nice big vegie patch and an orchard. Chickens supply eggs and carry out pest control in the garden.

Waste wood was also used to make the post and rail fencing around the property:

After the tour they helped us pack up the tree guards and stakes. Here's what we came home with:

It was great to meet Trent and Vikki and see a couple putting into practice their values of trying to live sustainably and treading lightly on the earth. 

Installing batteries at PragSust HQ

We've started the design process to install batteries at our house in Melbourne's suburbs. We thought it might be useful to discuss why we're doing this and to describe the process so others can learn from what we find.

The electricity grid in suburban Melbourne is very reliable with generally very good quality power supply. But there are those pesky greenhouse gas (GHG) emissions. As most of Victoria's electricity is generated from burning brown coal or lignite, as judged by GHG emissions Victoria has one of the dirtiest electricity supplies on the planet. By installing PV's, efficient appliances and lighting, using Green Power and some behavioural measures we've gradually reduced our GHG emissions from electricity to zero. And we have an electric oven (with gas cooktop), instantaneous gas boosted solar hot water and an efficient wood heater so we use very little natural gas.

So why install batteries? The first point to emphasise is that we're not aiming at grid independence. We think grid independence is unrealistic as a standalone system with just batteries and PV's at our house. Mr PragSust has built a detailed multiple renewables and storage modeling tool as part of a research project. This can use cost and performance data from batteries, PV's and other intermittent renewables and despatchable renewables such as bioenergy systems to model what a system costs to meet energy demands. The tool matches energy demand and generation data at half hourly intervals over a year.  PV's obviously don't generate at night. Cloudy periods during the day or over many days in winter can reduce PV generation to almost zero. So the only way a PV system can meet demand when the sun isn't shining is to have storage. But coping with extended low insolation periods very soon shows that a very large array and storage capacity is required. Even though PV's have become much cheaper and battery costs are decreasing,  the capital cost of installing a large PV generation and storage system is still prohibitive for most. 10kW is 40 250W panels. Finding space on a suburban block to fit 40 north facing panels is challenging. Let alone where to put a large battery pack. We only have weather records since the 1800's in Melbourne. The climate change models predict significant changes in Melbourne's weather which some argue have already started. What would we do if we had sized a PV-storage system for 5 days with no sun but we had 6 days of low insolation?

People on rural sites in Australia with no grid power have been running Remote Area Power Supplies (RAPS) for decades. But these tend to have generator backup for periods without sun and often these homeowners will have a very strong focus on reducing electricity consumption. Everyone in a suburban street buying a good quality generator capable of charging batteries would be a very inefficient use of resources. And while PragSust strongly supports and practices reducing energy consumption, whether the good people of Melbourne are prepared to be as ruthless on their power consumption as many RAPS sites is moot. And does it make sense to tie up large amounts of money in a stand-alone system where most of its capacity is designed to be used only for a small percentage of the year?

To get serious about sustainability we need solutions that are scalable, cost-effective and widely implementable. PV's are an excellent example of a technology that meets these criteria. So how do we think batteries can be usefully deployed with PV's while still maintaining our grid connection?

New PV systems in Victoria will receive a feedin tariff of only ~6c/KWH from 2015. (Possibly with a topup from some retailers.) Typical electricity tariffs in Victoria are around 12-15c/KWH offpeak and 25-30c/KWH peak. And at PragSust HQ we've chosen to pay about 3c/KWH extra for Green Power. So even after energy losses charging and discharging the batteries, there can be a financial benefit from storing excess PV generation and using battery power to replace peak demand currently supplied from  the grid. The electricity bills for larger electricity users may contain charges based on their peak demand during a half hour over a billing period. This reflects the  cost to the electricity supply industry of having supply capacity large enough to cope with this peak. Batteries can supply power during these peaks. This is sometimes called  shaving the peaks. As well as saving money for the electricity customer by removing the peak access charges, smoothing these peaks has a powerful and profound influence on the overall cost of the electricity supply system. Total generation capacity can be smaller. This is a significant saving. Several billion dollars worth of generation capacity in Victoria is only used for small amounts of the year. But this generation capacity has to be paid for so electricity bills are higher to reflect this cost.  The transmission and distribution network has to be sized to meet these peaks. Again, this cost can be much lower if batteries are used to meet peaks. Electricity has become a lot more expensive in Australia over the last ten years. Much of this price increase is due to new transmission and distribution infrastructure. There is now a regulatory requirement to determine the lowest cost means to alleviate perceived electricity infrastructure constraints. Batteries are one viable technology in some situations.

We need more information from actual sites with batteries in Melbourne to help make informed decisions about high penetration and 100% renewable energy systems. While modeling is useful, factories can't run on a spreadsheet. Extensive monitoring and data collection can generate information of great assistance to other electricity users, policy makers and investors.

And going back to the micro from the macro, having a system capable of supplying electricity during the occasional interruption to our electricity supply is useful.

We'll describe our progress with the battery installation in later posts. We hope this will be interesting and useful to other people contemplating battery installation.

Taking a home, building, community, region or nation towards 100% renewable

Mr PragSust has been doing stuff in renewable energy off and on for several decades. There's a lot of interest in Australian communities in moving towards 100% renewable.  PragSust HQ has been carbon free for some time with a biomass heater, PV's and solar hot water. And we've reduced our energy use through various energy efficiency measures. Generally speaking, reducing your energy consumption, using Green Power and installing renewables such as solar hot water and photovoltaics will reduce your emissions. But if you would like to be a bit more systematic, here's a list of steps that might be useful as an initial checklist at a number of scales.

a/ Characterise the energy use at the site in question. As the old saw has it, if you can't measure it you can't manage it.

• How much energy is used.

• When is the energy consumed within a day, in a week and across the year.

• What sort of energy ie thermal or electricity. 

• How much does the energy cost.

b/ Identify energy efficiency measures. As per the perky little aphorism from several decades ago, "Weatherise before you solarise." In Melbourne, companies such as ecoMaster and ecomad specialise in these assessments for residential and commercial buildings. PragSust HQ has had help from both companies with pleasing results. Specialist companies are available to do thorough assessments for industrial and large commercial sites.

c/ Reduce energy use by implementing cost-effective energy efficiency measures. It's a lot easier to find a cheap, cost-effective, practical renewable solution for smaller energy demands. Australian houses, for example, are generally appallingly inefficient with respect to thermal performance ie they leak heat like a sieve. Heat goes out in winter and comes in during summer. There's nothing sexy about roof, wall and underfloor insulation but it is very effective if good quality and properly installed. Weatherproofing to reduce draughts is simple and effective if done properly. In Australia's generally mild climate a well-designed, well-built house achieving HERS 9+ stars or PassivHaus (Australian Passive House Association and Passivhaus Australia have local introductory information on the PassivHaus approach) should need little to no heating and perhaps a small amount of air-conditioning in hot weather. Other measures such as LED's and energy efficient appliances are nice and easy. For larger industrial and commercial energy users, energy efficiency companies say it's not uncommon for them to find 30% reductions in energy consumption at these sites with quick payback periods.

d/ Determine the residual energy demand.

e/ Characterise renewable energy available at the site including any seasonal variations. Renewable energy sources available might be biomass, solar, wind and so on. Each of these sources will have scales and technologies that suit particular demands.

f/ Cost-effectively match the energy sources available with the demands.

• Is storage cost-effective? This might be thermal storage in a tank, battery storage for PV's or hydro storage at larger scale. 

• Can excess generation be sold? For example, feedin tariffs for excess PV generation beyond onsite consumption. Anther example is industrial parks like the one in Gussing, Austria to use process steam from a biomass CHP system.

• Can any demand be deferred or scheduled to match with generation from an intermittent energy source such as solar?

g/ Have the renewable system installed by a reputable company that will do a good job. PragSust has had excellent results from Corospark for various residential-scale renewable systems. Corospark are also doing PV installations at 100kW scale for commercial sites, energy efficient lighting refits for residential and larger sites and voltage optimisation systems for large energy users. Going Solar are designing and installing solar hot water systems for larger sites including school campuses and apartment buildings.

h/ Identify how to meet the demand remaining after deploying cost-effective renewables.This might be from a Green Power scheme.

Rinse and repeat!