Diamond Energy Review – Green Credibility or Hidden Cost?

Estimated reading time: 5 minutes

Published: 3 September 2025 — A rigorous Diamond Energy Review supported by real-world bill data and industry insight.

Quick Review of Diamond Energy

About Diamond Energy

Diamond Energy presents itself as the renewables-first challenger in Australia’s electricity market. The company highlights its Australian ownership, local customer service, and commitment to clean energy. For many environmentally conscious households, these values are appealing.

However, the “greenest” claim doesn’t apply to every customer by default. In practice, Diamond Energy offers two separate options:

1. Standard Plan – This is the default electricity supply, which still comes from the regular grid mix (coal, gas, renewables combined). Customers on this plan are not directly buying 100% renewable energy.
   
2. GreenPower Add-on – Customers can choose to pay extra (50% or 100%) for accredited GreenPower. This is a form of carbon-offsetting, where Diamond Energy purchases renewable energy certificates on the customer’s behalf.

This means that although Diamond Energy promotes itself as ‘the greenest,’ only customers who pay extra for 50% or 100% GreenPower are actually funding additional renewable generation. In reality, the default plan still draws from the standard grid mix. 

This gap between marketing and reality is a classic example of greenwashing—using sustainability claims that don’t reflect the everyday customer experience. For a deeper dive into how greenwashing works in the energy sector, see our related blog: What is greenwashing in electicity? “And when we strip away the branding and examine real bill comparisons across states, a different picture emerges: Diamond Energy’s plans are consistently more expensive than the cheapest market options. The trade-off? Values and simplicity, at the cost of annual household savings.

Diamond Energy Pricing Review – State-by-State Comparison

Victoria (VIC)

In VIC, competition is fierce, and households switching to the cheapest plan save an average of 14% annually. Even though Diamond Energy promotes transparency and renewables, customers in cities like Camberwell and Traralgon are paying hundreds more without gaining additional benefits unless they pay even more for GreenPower. Over a 3-year period, that’s up to $864 lost — the equivalent of a new washing machine or several months of groceries.

New South Wales (NSW)

NSW has some of the highest average household bills in the country, so overpaying by nearly $500 is a serious hit. For families in Mosman or regional towns like Smithtown, Diamond’s costs pile on top of already expensive charges. This scale of overpayment is hard to justify when cheaper plans exist with the same reliability of supply.

Queensland (QLD)

QLD customers often believe that time-of-use or controlled-load tariffs will maximise savings, especially for households with pools or off-peak hot water. But with Diamond Energy, none of the tariff structures beat the cheapest alternatives. The average household in Brisbane paying $400 extra could instead put that towards offsetting their own solar battery repayments — a far better long-term sustainability choice.

South Australia (SA)

SA already has some of the most expensive power in Australia, with heavy reliance on renewables but also high wholesale volatility. Diamond Energy customers here are paying an additional 20% more than the cheapest options. Over a years, that’s over $500 lost, which undermines Diamond’s positioning as a “fair” provider.

Diamond Energy Review: Just How Much Extra Are People Paying?

Across the board, Diamond Energy positions itself as “green and fair,” but the reality is higher annual costs:

• VIC: $221–$288 more for electricity
  
• NSW: $469–$529 premium across distributors
  
• QLD: $284–$423 higher depending on tariff type
  
• SA: $484–$521 more per year
  

Why It Matters

• Green isn’t default. Unless you pay extra for 50% or 100% GreenPower, Diamond Energy’s standard plan is just regular grid electricity. This means customers who want to be genuinely green end up paying twice — first through Diamond’s already higher base rates, and then again through GreenPower surcharges.
  
• Loyalty costs bite. Like other providers, staying static means overpaying — Australians lose on average $238/year by not switching (ACCC).
  
• Green ≠ cheapest. While their environmental story is strong, it doesn’t offset the consistent cost gap.
  

Customer Service – What Works and What Doesn’t

Strengths:

• Local ownership and customer service, Australian-based support.
• Good reputation among environmentally focused customers.

Weaknesses:

• Prices consistently above market-leading offers.
• Limited discounts or promotions compared to major competitors.
• Mixed digital tools: customer portal works but lacks advanced app features.

Final Thoughts – Where Energy Umpire Comes In

At Energy Umpire, we specialise in independent energy comparisons that cut through the branding. Our data-driven reviews highlight where suppliers like Diamond Energy fall short on cost.

In essence:

• Diamond Energy’s green commitment is genuine.
  
• But households are consistently paying hundreds more than necessary.
  
• The real savings come from comparing and switching regularly, not locking into a single “feel-good” brand.
  

That’s why Energy Umpire exists — to hold providers accountable and keep you on the genuinely cheapest plans available.