Designing an effective renewable energy system before making decisions is key for organisations aiming to reduce operational costs, enhance energy efficiency and ultimately achieve net zero emissions. This guide dives into the critical aspects of renewable energy system design, taking you through the key components, the storage considerations and the common ways of funding systems.
Key components of renewable energy systems
Designing an efficient renewable energy system involves integrating several key components to ensure optimal performance and sustainability.
Understanding Energy Usage
Having a detailed view of the current and future electricity demand on site is fundamental to ensuring that systems are sized appropriately and not left redundant when the site demand changes. It is essential that assets are designed to allow for the future electrification of heating and transport. Without this, businesses run the risk of having stranded assets on site or having to redesign or reinstall systems in the future.
Source of energy
Selecting the right renewable energy source requires more than simply evaluating climate or location—it’s about utilising the available space, understanding future requirements and aligning energy generation with your site’s operational profile and long-term goals.
For instance, while solar PV systems are ideal for facilities with large, unshaded rooftops and daytime energy demand, wind turbines may better serve rural sites with open landscapes and consistent wind flow.
Hybrid systems that combine solar and wind are increasingly popular, offering complementary generation profiles to balance intermittency. Advanced modelling tools can analyse site-specific data to optimise energy source selection, ensuring maximum efficiency and return on investment.
Energy storage
Integrating energy storage, particularly lithium-ion batteries, is essential for ensuring a steady power supply by balancing generation and demand. With their high efficiency and decreasing costs, these systems allow businesses to store surplus energy for use during low-generation periods, improving reliability and enabling greater energy independence. Properly sized storage also enhances operational resilience and optimises renewable energy utilisation both now and in the future.
Without storage, onsite generation is often undersized to ensure that the site can consume the power at the point of generation. With a BESS in place, generation can afford to be much larger, utilising all available space and together with the battery, offset more of the site’s demand.
Energy management system
Advanced Energy Management Systems (EMS) provide real-time oversight and control of energy production and consumption by linking supply and demand with the onsite flexibility. By optimising operations based on energy availability and demand, EMS improves efficiency and ensures smooth integration with your infrastructure.
A centralised holistic EMS is essential to enabling greater energy utilisation, maximising revenue streams and ensuring that all assets are appropriately sized and can communicate over a central platform. These systems enable smarter decision-making, reduce waste, and maximize the benefits of renewable energy investments.
Energy trading platform
Energy trading platforms enable businesses to sell surplus energy back to the grid at peak times or to other consumers, turning excess production into a revenue stream.
Without an energy trading platform, businesses are exposed to solar cannibalisation, reducing export prices year-on-year.
By actively participating in energy markets, businesses can offset costs while supporting grid stability, particularly during peak demand. These platforms also enhance flexibility, ensuring renewable energy systems deliver both operational and financial value.
Auxiliary services
Auxiliary services, such as inverters and transformers, are essential for converting and distributing energy within the system. They ensure that the generated renewable energy is compatible with the grid and meets the required quality standards.
End-of-use plan
Developing an end-of-use plan addresses the decommissioning and recycling of system components after their operational lifespan. This approach promotes environmental responsibility and compliance with sustainability goals by minimising waste and enabling the reuse of materials.
This isn’t an exhaustive list, however, integrating these components thoughtfully results in a cohesive renewable energy system that maximises efficiency, reduces costs and supports the transition to sustainable energy solutions.
Energy storage considerations
Battery Energy Storage Systems (BESS)
Lithium-ion batteries dominate the energy storage landscape in Europe due to their superior energy density, declining costs, increasing cycle life and safety.
For commercial and industrial applications, these batteries offer the reliability and safety needed to store excess renewable energy for use during periods of high demand or low generation.
Europe’s focus on battery innovation is evident in projects like the European Battery Alliance, which aims to develop a competitive and sustainable battery value chain. This push has led to significant cost reductions, with battery storage prices falling by over 85% since 2010. Additionally, advanced battery systems are now designed to integrate with energy management systems (EMS), ensuring maximum efficiency.
Integration with renewable energy sources
Integrating energy storage with renewable energy sources ensures seamless operation and addresses the intermittent nature of renewables. Solar and wind energy, for instance, are inherently variable; solar depends on daylight hours, while wind generation fluctuates with weather conditions.
Batteries bridge this gap by storing excess energy during periods of high generation and dispatching it during low generation or peak demand.
DC coupling
A DC coupled solar and battery design can enable businesses to overcome grid constraints. Allowing for greater deployment of solar and wind generation coupled directly to the battery.
Storage system sizing and capacity planning
Accurately sizing an energy storage system is essential for commercial and industrial (C&I) sites, to ensure a future proof energy system and to ensure it meets the site’s operational needs without unnecessary overspending.
Here’s a practical, streamlined approach:
- Define the battery’s purpose(s)
- If the goal is peak shifting, calculate how much energy you need to store during off-peak hours to meet demand during high-cost peak periods.
- For backup power, determine the critical loads that need to be supported and for how long during an outage.
- For maximising self-consumption, calculate the gap between renewable generation and demand, especially during evening or non-solar hours.
- Analyse your energy demand
- Use historical half hourly data to understand your site’s energy consumption patterns in today’s environment but also in the future when heat pumps or EV charging infrastructure is added.
- Accurately forecast and renewable energy output (e.g., solar or wind) to identify how much surplus energy is available for loadshifting and to ensure generation assets are sized appropriately
- Calculate the storage capacity required
- Estimate daily energy surpluses (e.g., kWh generated by solar panels minus demand) to determine the minimum battery size.
- Include efficiency losses (lithium-ion batteries typically have 85–95% efficiency) and add a buffer for future degradation (e.g., 10–20% over 10 years).
- Predictive tools to simulate performance
- Use sophisticated modeling software or predictive tools to simulate performance, generation, load and revenue streams for financial payback, ensuring the system aligns with your future operational goals.
Again, this isn’t an exhaustive list of steps, it’s more a practical idea of the process involved in renewable energy system design to help confidently size energy storage systems, balancing operational needs with cost efficiency and long-term energy independence.
Economic considerations of system design
Renewable energy systems offer significant financial and environmental benefits. Transitioning to renewables also lowers carbon footprints, helping businesses meet sustainability goals and enhance corporate social responsibility, creating both economic savings and reputational advantages.
When considering financing options for renewable energy system design, businesses can explore several models depending on their financial strategy, capital availability, and risk tolerance. Here are the most common financing options for renewable energy projects:
Capital purchase (self-funding)
Businesses pay for the system upfront, owning it outright. This maximizes long-term savings, allows full control of the system, and ensures access to government incentives such as tax credits or grants. While it offers the highest IRR, it requires significant capital investment and carries some financial risk if the system underperforms.
Power Purchase Agreement (PPA)
A third-party provider funds, installs and maintains the system onsite, while the business purchases energy at a fixed, typically lower-than-grid rate. This eliminates upfront costs, provides immediate savings, and locks in predictable energy pricing for 10–25 years. However, the business does not own the system or directly access tax benefits.
Price Protect renewable electricity tariff
A unique solution provided by Wattstor goes beyond a standard power purchase agreement, guaranteeing lower than market priced electricity for the duration of the contract.
This unique renewable energy tariff goes hand in hand with a well designed renewable onsite energy system, covering 100% of the site load and providing a price cap and floor. This allows customers to benefit from price dips while avoiding price spikes.
Learn more about Price Protect »
Conclusion
Designing a renewable energy system is a complex but highly rewarding process that delivers financial, operational, and environmental benefits for businesses. By integrating the right components; energy sources, storage systems, management tools and auxiliary services. Tailoring them to your specific needs, organizations can reduce energy costs, maximize efficiency, and support sustainability goals.
Whether you aim to reduce grid dependency, achieve net zero goals, or secure energy independence, the insights in this guide hopefully have provided a foundation to take actionable steps toward a more sustainable and profitable energy future.
Wattstor is here to help you navigate the journey with expertise, innovative technology and fully financed solutions with proven success stories to make your renewable energy vision a reality. Contact us today to start transforming your energy strategy.
Author
Jack Peck
Head of Sales, UK & Ireland
Jack Peck has over a decade’s experience in the renewable energy sector. Starting out as a solar developer, he has spent the past five years bringing battery storage solutions to market and now heads up Wattstor's sales team in the UK.