Solar Energy

Solar Energy is used commonly to generate electricity via solar photovoltaic (PV) panels. Most people are familiar with the benefits of solar PV. Rooftop solar PV installations are applied to many residential and commercial buildings.

We use solar energy to assist in reducing the grid supplied energy to residential and commercial buildings. Similarly, we use solar PV coupled with battery storage to assist with load shifting and off grid buildings. The more efficient we make the geothermal heating and cooling in a building the less solar generated electricity we need to run a system. 

By optimising overall air conditioning and hot water production, we can operate the building for longer with fewer solar panels and less battery storage than conventional systems.

Solar PV

Solar PV has been promoted by successive Australian Federal governments via a Renewable Energy Certificates (RECs) Scheme which considerably reduces the cost of solar energy for home and business owners. It is now a widely accepted way of reducing energy bills especially for daytime power usage, when the sun is shining. The extent of benefit from solar PV is based on location, with some places being a lot sunnier than others. The time of energy use is important to gauge overall benefit, with daytime use of energy being best offset by daytime solar.

Increasingly, we are seeing battery storage being coupled with solar PV systems for load shifting (use of daytime energy in the peak load evenings). This is an aspect of solar power systems that is becoming more relevant as battery storage costs reduce over time.

100kW Solar PV supporting a gas-less upgrade of Shopping Centre HVAC system, Wallan, Victoria (Direct Energy Australia 2021)
100kW Solar PV supporting a gas-less upgrade of Shopping Centre HVAC system, Wallan, Victoria (Direct Energy Australia 2021)

Commercial scale solar PV

Commercial scale solar PV is very popular. Many business realise that with high daytime energy usage, solar power can be used directly without need for any feedback to the electricity grid. This is when solar power works best for a commercial enterprise. Shopping centres, factories, aquatic centres and office buildings can benefit substantially from solar PV and achieve payback periods for installation cost of less than 5 years in many cases.

Undertaking an energy load analysis is an important part of design if optimally sized systems are to be installed. The feed in tariff is also very important.

This is how much an electricity retailer will pay for solar energy derived electricity from its clients, on the rooves of factories, shopping centre carparks and office rooftops etc. If this is high, there can be benefit in generating more electricity than a building uses. If the feed in tariff is low, there may be limited benefit in oversizing a building.

Large utility scale solar PV

Large utility scale solar PV is also becoming very common. Solar farms serving large communities are being installed Australia wide, with many being owned by prominent energy industry utility companies.

Emerging in the precinct energy market are large scale roof top solar arrays that can be managed by energy utilities and coupled with behind the meter or community battery storage systems.

10kW Residential Solar PV installation, Bowral, NSW
Solar, 60 kW, & Battery System, 100 kW/h installation at remote Western Australian indigenous community: the State’s first major roof top off grid stand alone power system delivered in an indigenous community. Application: Aged Care and Community Administration Centre (Direct Energy 2020)

Off-Grid Solar PV

This is an emerging sector, as renewable energy is leveraged further in remote communities and in areas that have limited grid energy supply. We utilise solar PV and battery storage systems to assist in creating off-grid environments.
It is very difficult to cater for 100% of energy loads with renewable energy all year round. Solar PV in mid winter can lose over 90% of its energy generating capacity on cloudy, rainy days. Other forms of energy generation must be utilised during these times.

We view off grid solar energy & battery storage as a very effective resource, when diesel fuel or gas are the only alternatives. It directly displaces diesel as a source of energy and has a significant direct impact on the carbon emissions of a community.

Solar and Geothermal: Energy Relationship

In large scale estates, our geothermal systems or district geothermal systems offer the equivalent energy reduction of a 2.5 Megawatt solar PV system per 1000 homes. In other words, it achieves energy reduction of having 2.5kW of solar PV on a standard home in constant use. However, unlike batteries and solar PV, a district geothermal system lasts for +50 years with only a single replacement of the heat pump and solar PV systems within this period. Conventional hot water systems and air conditioners will need replacement between 3 and 4 times over the same period. The reduction in energy requirement of geothermal systems is very significant, as it is known as the most efficient heating/cooling technology in the world. Geothermal enables roof top solar power generation to heat/cool a home for longer on the same solar energy input. It establishes power grid stabilisation by substantially reducing ‘peak load demand’ and reduces the cost of electrical infrastructure in any housing development. By coupling solar PV and battery energy storage with district geothermal heating and cooling systems, the optimal energy efficiency for a home or building within a residential precinct/town can be achieved. The difficulty is dealing with peak loads in remote inland areas that experience low winter temperatures (sub zero) and very high summer temperatures (+40C consistently). The high peak energy loads in winter put a lot of pressure on the solar and diesel energy systems. This is also coupled with dust issues in desert areas. Cleaning of the panels can be automated, but this adds additional cost. All challenges can be overcome, depending on the objectives of the project. Our internal company mandate is to significantly reduce peak loads by applying district wide geothermal systems that offer over 30% peak load reduction in summer and winter. This corresponds to a reduction in overall electrical consumption of a community by over 20%. This assists markedly the performance of off grid remote stand-alone power systems and optimises the usage of all equipment on site.